Electrocardiography (ECG) is the recordation and analysis of the electrical potential of a patient's heart and is one of the most widely used patient physiological monitoring techniques in healthcare today. In ECG, the electrical potentials of various regions of the heart are monitored through the use of electrodes to obtain data that is indicative of the depolarization and repolarization of the heart muscle tissue. Interpretation of this physiological data can be used to identify many cardiac conditions including, but not limited to, ischemia, myocardial infarction, drug toxicity and arrhythmia. An ECG signal comprises more than the mere collection of biopotentials. Rather, an ECG signal comprises a differential measurement referred to as a lead that measures the voltage across the heart between a reference location and a measurement location. Each of the resulting differential leads are denoted by a reference to the physical location of the electrodes used in obtaining that lead.
In a typical 12-lead ECG measurement, ten electrodes are used to obtain the twelve leads. These electrodes include the standard electrode placements at the right arm (RA), left arm (LA), left leg (LL), and right leg (RL). These standard electrodes are supplemented by the addition of six precordial electrodes that are placed at specific locations around the patient's chest and are denoted by the indications V1, V2, V3, V4, V5 and V6. The standard electrode placement yields measurements of the three standard ECG leads including lead I (LA-RA), lead II (LL-RA), and lead III (LL-LA). The standard electrode placements may also be used to obtain the three augmented ECG leads which are the unidirectional potential vectors starting at the average between two electrodes in the direction of the third electrode. These include aVR, aVL, and aVF.
One problem with obtaining ECG measurements is that typically ten wires corresponding to the ten electrodes attached to the patient must be used in order to obtain the twelve lead ECG as just described. This is a cause of many of the problems associated with obtaining ECG measurements. The large number of wires extending from the patient restricts the patient's movement. A large number of wires may restrict where the patient may place his/her arms and where and how the patient may move about a hospital bed or room. For example, when a patient is sleeping, the wires may restrict the positions in the hospital bed in which the patient may lie, thus leading to an uncomfortable night's sleep and slower recovery.
Alternatively, due to patient movement or clinician movement about the patient, the wires may become tangled. Tangling of the wires may lead to electrode and/or wire damage. Electrode or wire damage may result in inaccurate physiological data recordation leading to reduced clinician ability to diagnose the patient's condition. Furthermore, tangled wires may require additional clinician time in removing, untangling, and replacing the tangled electrodes and lead wires with new connections. Additionally, a large number of wires may result in the wires becoming tangled while they are in storage and as such, a clinician must spend time before the initial application of the wires to the electrodes to untangle the wires. The propensity of the wires to become tangled also increases the chances of damage to the lead wires. In many instances, if a single lead wire becomes damaged or broken, the entire lead wire set must be replaced at additional cost because the lead wires are individually associated with a specific ECG electrode anatomical location.
The problem of tangled and/or damaged wires connected to ECG leads is most prevalent in situations involving the monitoring of active patients and/or the long term monitoring of a patient's ECG characteristics. The more active a patient is the greater the likelihood that wires extending from ECG electrodes may become tangled and/or damaged. Similarly, the longer wires are connected to a patient the greater chance that these wires may become entangled and/or damaged. One example of this situation is in monitoring the patient's ECG overnight. The electrodes and wires are connected to the patient for a long duration of time and the patient may be prone to move in his/her sleep thereby entangling and/or damaging the wires or electrode connections.
Another specific example where the management of wires extending from electrodes is a concern is in body surface potential mapping (BSPM). BSPM provides a more in-depth ECG analysis than a typical 12-lead ECG, as BSPM is typically performed using between 20 and 128 or more electrodes connected to the patient at varying anatomical locations. The purpose behind BSPM is to acquire localized effect information from the heart as opposed to the primarily three dimensional information of the heart taken by a twelve lead ECG. Due to the greater amount of data collected, BSPM is more effective in detecting instances of ischemia and infarction than a twelve lead ECG.
The collection of electrocardiographic data from such a large number of electrodes however, has proved to be burdensome. One method used is to individually attach each electrode and a corresponding lead wire as a scaled up version of a typical twelve lead ECG. If the aforementioned problems exist with respect to ten wires connected to electrodes, than it is obvious that these problems are only magnified as each electrode and lead wire is added to the patient, potentially to more than 128 electrodes and lead wires. Alternatively, a vest or other garment may be utilized that comprises electrodes integrated into the garment that may collect physiological data from the skin of the patient. However, a standardized vest or other garment is limited in that the correct anatomical placement of the electrodes will not be achieved unless the garment is an adequate fit for the patient. Furthermore, the electrode connections with the skin of the patient may be limited as movement between either the patient and/or the garment may pull the electrode away from contact with the skin of the patient. Finally a further limitation of the present BSPM garments is that since it is difficult to manage the exact anatomical placement of the electrodes, it is even more difficult to obtain a twelve lead ECG from the proper anatomical locations to utilize as a reference for the rest of the physiological data collected during the BSPM procedure.
Therefore, it is desirable in the field of collection of physiological data from patients to provide an apparatus and system for limiting the tangling and/or damage to wires extending from the electrodes. It is further desirable in the field to provide an apparatus and/or system that improves the mobility of the patient without tangling or damaging the wires. It is also desirable to have an anatomical reference to the location of the electrodes.